Senior Information Systems Security Engineer

Leidos LLC; United States; On-site; USD 131,000 - 237,000; Full time

Job summary

Leidos is seeking a Senior Information Security Systems Engineer to join a small team providing IA architecture analysis and security engineering support for NC3, COG, and senior leader communications. The ISSE will act as a consultant, delivering technical expertise to the customer and guiding security objectives and accreditation activities.

The role requires extensive DoD experience, strong RMF and risk assessment skills, and the ability to work independently with minimal direction.

Qualifications

• BS degree with 14+ years of ISSE/SE experience in DoD programs.
• Must hold CISSP or CASP certification.
• Strong written and briefing skills for senior DoD officials.

Responsibilities

• Conduct cybersecurity risk assessments and provide risk mitigation recommendations.
• Support design, implementation, and operation of real-time threat capabilities.
• Analyze candidate architectures for security gaps and mitigations.
• Research emerging technologies for cybersecurity effectiveness.
• Develop and refine innovative security solutions with stakeholders.
• Engage stakeholders to define security objectives and validation methods.
• Validate system security requirements and assist in IA design and accreditation.

Skills

Technical writing

Briefing to DoD

RMF expertise

Network security

Independent work

Zero Trust

Cloud computing

Risk assessment

Education

BS in CS/IA/ISSE field

CISSP or CASP certification

Job description

As a Senior Information Security Systems Engineer (ISSE) you will join a small team of security engineers providing Information Assurance (IA) Architecture Analysis and Security Engineering Support for the implementation and fielding of the National Leadership Command Capability in support of Nuclear Command, Control, and Communications (NC3), Continuity of Government (COG), and Senior Leader communications. The ISSE will perform in a consultant like role providing technical knowledge, expertise and advice to our customer.

Original Posting: August 27, 2026

For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above.

Step 10 is ancient history. We're already at step 30 and moving faster than anyone else dares.

Primary Responsibilities:

• Conduct cybersecurity risk assessments and provide prioritized risk mitigation recommendations in support of the customer’s mission.
• Support the design, implementation, and operation of real-time capabilities to discover, detect, analyze, and mitigate threats and vulnerabilities.
• Analyze candidate architectures by evaluating against defined security requirements to identify security gaps, and provide recommended mitigation strategy.
• Research and evaluate candidate emerging technologies to determine cybersecurity effectiveness.
• Aid stakeholders through the development, refinement, delivery, and implementation of innovative solutions and capabilities.
• Engage stakeholders to ensure security objectives, protection needs, security requirements and associated validation methods are defined.
• Validates and verifies system security requirements definitions and analysis and establishes system security design Designs, develops, implements and/or integrates IA and security systems and system components including those for networking, computing and enclave environment to include those with multiple enclaves and with differing data protection/classification requirements Assist architects and systems developers in the identification and implementation of appropriate information security functionality to ensure uniform application of Agency security policy and enterprise solutions Contributes to the security planning, assessment, risk analysis, risk management, certification and awareness activities for system and networking operations Reviews C&A documentation, providing feedback on completeness and compliance of its content

Qualifications

• Bachelor of Science degree from an accredited university ideally in Computer Science, Information Assurance, Information Security System Engineering or related field with a minimum of 14 years of experience as an Information Systems Security Engineer (ISSE) or System Engineer on programs and/or contracts with the customer space CISSP OR CASP certification required.
• Strong writing skills Confidence and ability to present briefing to senior level DoD officials in both prepared briefings and/or in ad hoc discussions.
• Expertise in the Risk Management Framework (RMF) and conducting cybersecurity risk assessments.
• Expertise in network technology and systems security engineering.
• Experience in identifying, researching, characterizing, and documenting security weaknesses related to operating systems, software applications, firmware, network hardware components, as well as network architecture design to identify protection needs and documented policies and procedures.
• Experience developing and documenting system security requirements and conducting requirements gap analysis.
• Experience with security monitoring and incident response capabilities.
• Experience with emerging technologies such as Zero Trust, Cloud Computing, etc.
• Knowledge of, and practical experience with the NIST Special Publications 800 Series, CNSSI 1253, and DoD 8500.
• Ability to work independently within a schedule and with little direction.
• CLEARANCE REQUIRED: Active TS/SCI with polygraph.

Pay Range

Pay Range $131,300.00 - $237,350.00

The Leidos pay range for this job level is a general guideline only and not a guarantee of compensation or salary.

Pay and Benefits

Pay and benefits are fundamental to any career decision. That's why we craft compensation packages that reflect the importance of the work we do for our customers.

Employment benefits include competitive compensation, Health and Wellness programs, Income Protection, Paid Leave and Retirement.

More details are available here.

Securing Your Data

Leidos will never ask you to provide payment-related information at any part of the employment application process. And Leidos will communicate with you only through emails that are sent from a Leidos.com email address. If you receive an email purporting to be from Leidos that asks for payment-related information or any other personal information, please report the email to [e-mail].

Commitment and Diversity

All qualified applicants will receive consideration for employment without regard to sex, race, ethnicity, age, national origin, citizenship, religion, physical or mental disability, medical condition, genetic information, pregnancy, family structure, marital status, ancestry, domestic partner status, sexual orientation, gender identity or expression, veteran or military status, or any other basis prohibited by law. Leidos will also consider for employment qualified applicants with criminal histories consistent with relevant laws.

About Leidos

Leidos Leidos is an industry and technology leader serving government and commercial customers with smarter, more efficient digital and mission innovations. Headquartered in Reston, Virginia, with 47,000 global employees, Leidos reported annual revenues of approximately $17.2 billion for the fiscal year ended January 2, 2026. For more information, visit www.Leidos.com.